Automatic variable choke for gun barrels



Ich 18, 1947.

K. wHEDoN 2,417,721

AUTOMATIC VARIABLE CHOKE FOR GUN BARRELS Filed sept. 2s, 1944 i, I

l: 19.5- 3mm 2' /2' E] lENNETH WHEDUN E l- Patented Mar. 18, 1947 1.; airco stares ZAUJZE Arg ortica AUTOMATIC VARIABLE CHOKE FOR GUN 4IZRRELS 7 Claims.

The present invention relates to improvements in chokes for single barrel multiple shot fire arms, such as automatic and pump shotguns and the like, in which it is desirable to alter the pattern of the pelllets between the first and subsequent shots.

One of the objects of the present invention is to provide a variable choke for Shotguns and the like, which is automatically shifted from one position to another to change from open or modified barrel to full choke following the rst shot.

Another object is to provide an improved automatic variable choke of the type described in which the pressure of the gases is employed to automatically regulate the choke.

Another object of the invention is to provide an automati: choke for guns which is characterized by simplicity of construction and operation.

These and other objects and advantages residing in the construction, combination and arrangement of parts constituting the improved choke will be more fully appreciated from a consideration of the following specification and annexed claims.

In the accompanying drawing, wherein several forms of the present invention are illustrated,

Fig. 1 is a cross-sectional view of a gun barrel having installed thereon a choke ascording to the present invention,

Fig. 2 is a cross-sectional view taken on line II--II of Fig. 1.

Fig. 3 is a view similar to Fig. l showing the choke in a position following the rst shot,

Fig. 4 is a side elevational view of the colletlike portion of the choke construction,

Fig. 5 is a fragmentary sectional view showing the use of shims for locating the choke in the correct position on the threaded end of the `gun barrel, and

` ing the parts of the choke welded together prior to threading.

Referring to the drawing, in Fig. 1 the gun barrelV IIJ of a multiple shot automatic or pump gun has been externally threaded at l2 to receive the variable choke generally designated by referense character I4. In the illustrated form of the invention the choke I4 comprises an outer sleeve I6 whi :h is internally threaded at I8 to receive the external threaded portion of the collet 22. Preferably the collet 22 is of heat treated material to give it a relatively high resiliency, and is longitudinally split at 24. The collet 22 is preferably of uniform outside diameter tl; :oughout its intermediate portion and of slightly larger external diameter at its forward portion 26 with a riser 28 extending between the different size diameters. As more clearly shown in Fig. 1, the collet 22 is internally threaded at 38 to receive the externally threaded portion I2 of the gun barrel I0.

The sleeve I4 has a reduced diameter portion 32 at its outer end which functions to pilot the outer end of the collet 22, as defined by the spring metal finger portions 34. A longitudinally extending slot 36 milled in the sleeve I4 is provided to guide the sight 38 for back and forth movement along the choke I4, guided through a tongue portion 40 operating in the slot 36,

Secured to the sight 38 for unitary movement though a suitable fastening member 42 is a ring 44. The ring 44 is closely fitted in the annular chamber 46. At its forward end the ring 44 has a slight radius at 48 It0 assist in riding over the riser 28 and upon the portions 2B of the resilient fingers 34 of the collet 22.

In Fig. 3 the ring 44 is shown in its forward position having been advanced over the risers 28 to a point deflecting the fingers 34 inwardly to a full choke position.

In order to assure `the proper register of the sight 38 relative to the gun barrel I9 and the rest of the gun construction, one or more shims 50 may be inserted between the flange 52 of the collet 22 and the ends 54 of the sleeve I6. This arrangement is clearly shown in Fig. 5 and avoids any necessity of attempting to register the threading of the parts I8 and I8 so as to bring the sight 38 into the correct position when the engaging threads are tightly screwed together.

In Fig. 6 is shown a slight modification of the invention wherein the o'uter casing I6' of the choke is tightly fitted upon the collet portion 22 and hydrogen welded in a well-known manner to make the parts I6' and 22' integral. Thereafter the same are threaded as shown and screwed in position on the threaded ends l2' of the gun barrel I8'. Shims 50 for making the sight of the choke register with the parts rigidly screwed together are provided between the shoulder of the gun barrel andthe end 5B of the welded parts.

To describe the operation of my choke, after v the gun has been fired one or more times and it is desired that the rst shot red thereafter shall be with an open bore, the ring 44 is moved into the position shown in Fig. 1 by pressure applied against the sight 38 in a longitudinal direction rearwardly. The resiliency of the fingers 34 of the collet 22 will hold the ring 44 in the position shown in Fig. 1. At the time the gun is discharged, after the pellets have left the gun barrel Ill and the extension furnished by the choke, the pressure of the explosion which follows flows into the chamber 46 through the slots 24 and the pressure developed in the chamber 46 will be sulcient to move the ring 44 forward into the position shown in Fig. 3. Thus the explosive charge of the rst shot will automatically adjust the choke for the second and all subsequent shots to the full choke position. Thereafter the choke can be adjusted to full open position by pressure applied to the sight 38 to effect movement of the ring 44 back into the position shown in Fig. 1.

In bird shooting of the type which usually flush from cover, it is desirable to have the choke in open choke position for the first shot and in full choke position for the second and subsequent shots which will be normally taken at a greater range. It will be understood that the ring 44 functions as a piston in the annular chamber 46 and it is the pressure of the explosion in the chamber 46 acting against the piston-like ring 44, which acts as the sole K neans for automatically adjusting the choke from open to full choke position. Devices have been heretofore proposed in which the recoil has been utilized to operate a variable choke and also it has been proposed to employ the pressure of explosion to trip a spring-loaded variable choke. In my improved device, I have materially simplifled the construction and operation by relying solely upon the pressure created within the choke on the discharge of the gun for automatically operating the choke.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An automatic variable choke for a gun comprising a contractable sleeve which is adapted to l dene an extension of a gun barrel, an annular shaped piston embracing a portion of said sleeve and constructed and arranged lfor longitudinal movement thereon, an outer sleeve embracing said piston and defining with said first sleeve an annular cylinder, means for directing the pressure of discharge of the gun to said cylinder against said piston to move the piston longitudinally of said first sleeve, said rst sleeve being in the form of a plurality of resilient fingers, and means upon said first sleeve and said annular piston to deflect said fingers inwardly upon movement of said piston by said discharge pressure.

2. An automatic variable choke for a gun comprising a collet having a normally open position, axially movable collet closing means for restricting the passage in the choke, and means constituting an outer sleeve for confining and axially directing the pressure of explosion of the gun against said collet closing means to move the same from full open to full choke position, said collet closing means being within the outer sleeve.

3. An automatic variable choke for a gun comprising an outer shell, an inner shell spaced from said outer shell to provide an annular chamber therebetween, said inner shell being made up of a plurality of resilient lingers constructed and arranged to be urged inwardly from open choke to full choke position, an annular piston member embracing said inner shell and operating in said annular chamber, said inner shell and annular piston being constructed to urge said re ilient fingers inwardly upon relative axial moement between said inner shell and said pist n, and means for directing pressure of discharge into said chamber to move said annular piston.

44. An automatic variable gun choke comprising a collet-like member adapted to constitute an extension of a gun barrel and capable of being restricted, an annular piston-like member surrounding said collet and movable longitudinally thereof to open and close the collet member, cylinder means in which said piston-like member is housed, and means for axially directing the pressure of discharge against said piston-like member to move the same relative to said collet.

5. An automatic variable gun choke comprising a collet-like member constructed and arranged to be restricted, a collet closing member, an outer shell embracing said collet member in spaced relation thereto to dene an annular chamber therebetween, said collet actuating member being disposed in said chamber and functioning as a piston, and means for directing the pressure of discharge into said chamber to actuate said collet closing member.

6. An automatic variable gun choke comprising an outer shell, an inner shell in the form of a collet, a collet opening and closing member in the form of a ring embracing said collet member, means for directing the pressure of discharge against said collet closing member to move the same relative to said collet to close the same, a sighting device, and an operative connection between saidsighting device and said collet closing member for moving the same from one position to another.

7. In a choke for a gun, a sleeve-like member adapted to constitute an extension of a gun barrel constructed and arranged to be restricted, restricting means for said sleeve, a sighting device, and an operative connection between said sighting device and said restricting means for moving said means through movement of said device.

KENNETH WI-IEDON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED vSTATES PATENTS Cory Mar. 19, 1907 

